Can you spy on a phone when it is turned off?

Whether you consider Edward Snowden a traitor or a patriot, before he hit the news most people didn't give much thought to government spying on everyday citizens. During a recent interview, he said that the NSA has the ability to spy on your smartphone, even if it's turned off.

So the NSA can listen to your conversations and use your camera when you powered off your phone? Sounds crazy but it is possible — in a way.

The most likely way is with a type of invisible spying app. Spying apps aren't anything new; everyone from corporations to hackers to jealous exes use them.

This spying app though doesn't just steal your surfing history, text messages and photos. It also gives full access to your phone's microphone and camera.

Your phone basically becomes a bug that tells the NSA everything going on around you. Any conversation you have or any embarrassing thing you do, the NSA will have it recorded.

The worst part is that even if you turned the phone off to be safe, it wouldn't really be off. The app makes your phone pretend to be off — it turns off the screen, ignores incoming calls and doesn't respond to button presses — but the spying will still be going on.

Now, if you wanted to have a sensitive conversation without worry, you could remove the phone's battery. Then the phone would really be off. But, some phones, like the iPhone, don't have a removable battery.

Here's when you get to feel like a spy. To truly turn off an iPhone you have to know how to use the "device firmware upgrade" or DFU, mode. This is what Apple and developers use to install iOS updates, jailbreak a phone or unlock a SIM card.

Don't worry, you're not doing any of that. You just want to really turn off your iPhone.

To get into DFU mode, you'll need an iPhone, USB cord and a computer with iTunes installed.

First, connect the iPhone to your computer using the USB cord and start iTunes. Once iTunes is running, go to the iPhone and hold down the Power button for three seconds, then press the Home button. Hold both buttons and count to 10 seconds.

The phone's screen will go black, but keep holding the buttons. After the 10 seconds are up, let go of the Power button, but keep the Home button pressed.

Hold the Home button for another 10 to 15 seconds. When you see a pop-up message in iTunes, you know you're successfully in DFU mode.

When you're ready to get out of DFU mode, hold the Home button and Power button until the Apple logo appears. Then let the phone start like it normally would.

Of course, this turning on and off procedure is a complete hassle. So you might think it's better to keep the NSA or anyone else from putting the spy app on your phone in the first place. Good idea, but it's going to be tricky.

The NSA or anyone else after you could slip a spy app on your phone disguised as another legitimate app. This is easier to do on Android phones because they can download apps from third-party sites and Google Play's review policy is very relaxed.

Apple gadgets can only download from the Apple App Store, and the nefarious would have to get the app past Apple's reviewers. That's harder, but still isn't impossible.

Another concern is that the NSA knows undiscovered bugs in operating systems and common programs that lets it collect data without anyone knowing. It turns out the NSA was exploiting the Heartbleed bug to spy on people, so it isn't that farfetched. And it's just about impossible for you to stop.

In the worst case, the NSA could pull the same trick it allegedly uses with American-made routers heading overseas. The NSA intercepts a router shipment, puts a backdoor in the software, packages the routers back up and sends them on. Then it can spy on any networks the routers connect to.

I doubt the NSA is doing that to phones coming into the U.S. - it would be a logistical nightmare if nothing else - but you never know.

If you're really worried about spying apps, you might want to look into the newBlackphones. These Android-based phones are built from the ground up with security and privacy in mind.

Of course, once on the market, a Blackphone will set you back $630, so it isn't for the faint of heart or light of wallet. It might worth it, though, if it keeps the NSA out of your life – for now.

On the Kim Komando Show, the nation's largest weekend radio talk show, Kim takes calls and dispenses advice on today's digital lifestyle, from smartphones and tablets to online privacy and data hacks. For her daily tips, newsletters and more, visitwww.komando.com. E-mail her at techcomments@usatoday.com.